Formaldehyde (FA) is ubiquitous in the environment and is a chemical agent that possesses high reactivity. Occupational
exposure to FA has been shown to induce nasopharyngeal cancer and has been classified as carcinogenic to humans (group 1) on the basis of sufficient evidence in humans and sufficient evidence in experimental animals. The exposure to this substance is epidemiologically linked to cancer and nuclear changes detected by the cytokinesis-block micronucleus test (CBMN). This method is extensively used in molecular
epidemiology, since it determines several biomarkers of genotoxicity, such as micronucleus (biomarkers of chromosomes breakage or loss), nucleoplasmic bridges
(biomarker of chromosome rearrangement, poor repair and / or telomeres fusion) and nuclear buds (biomarker of elimination of
amplified DNA). The gene X-ray repair cross-complementing group 3 (XRCC3) is involved in homologous recombination repair of cross-links and chromosomal double-strand breaks and at least one polymorphism has been reported in codon 241, a substitution of
a methionine for a threonine.